Cattle Summer Mastitis: Prevention and Welfare Management of a Seasonal Disease

Summer mastitis affects dry cows and heifers during fly season, causing severe udder infection and welfare harm. Prevention through fly control and teat sealing is highly effective.

Key Facts

Summer mastitis is caused by bacteria introduced through teat orifices by head flies (Hydrotaea irritans) during summer months
Unlike lactational mastitis, summer mastitis affects dry cows and maiden heifers - animals not being routinely examined for udder changes
Causative organisms include Trueperella pyogenes, Peptostreptococcus indolicus, and Fusobacterium necrophorum - causing severe, typically fatal quarter infection
Clinical signs include severe swelling of affected quarters, foul-smelling discharge, fever, and rapidly deteriorating systemic illness
Affected quarters are almost always permanently lost - the infection is so severe that recovery of milk production is not expected
Death can occur from systemic sepsis if treatment is delayed
Prevention through fly repellents, pour-on insecticides, and internal teat sealants at drying off is highly effective
Paddock selection - avoiding wet areas and woodland where head flies congregate - reduces exposure during high-risk periods

Welfare Considerations

Summer mastitis causes extreme welfare harm: acute, severe septic infection causing intense local pain, systemic illness, and permanent loss of affected quarters. The welfare tragedy is that the disease is highly preventable through fly control and teat sealants, yet cases occur annually in dry cow herds that are visited less frequently than lactating herds. The reduced monitoring frequency for dry cows means infected animals may suffer for days before detection. Prevention through internal teat sealants at dry off - a procedure with minimal welfare cost - provides highly effective protection. Monitoring frequency for dry cows and heifers should increase during peak fly season (June-September in the UK) to enable early detection when prevention fails.

What You Can Do

Apply internal teat sealants (Orbeseal or similar) to all cows at drying off in areas with summer mastitis history
Apply fly repellents or pour-on insecticides to the udder region of dry cows and heifers during summer fly season
Move dry stock away from woodland edges and wet areas where head flies concentrate during summer months
Increase observation frequency of dry cows and heifers during June-September from weekly to at least twice weekly
Train stockpeople to detect early summer mastitis signs: swollen quarter, lethargy, or separation from the group
Treat affected animals immediately with aggressive systemic antibiotics and anti-inflammatories - early treatment reduces severity
Accept that affected quarters will not recover and focus treatment on saving the cow's life and other quarters
Ensure dry cow monitoring is assigned responsibility rather than assumed - management gaps are a primary cause of delayed detection